Wash the watermelon thoroughly.
Pat it dry.
Place it on a stable cutting board.
Cut off both ends to create flat surfaces.
Stand the watermelon upright and slice it into thick slabs.
Cut each slab into long strips.
Cut the strips into cubes by slicing crosswise.
For wedges, cut the watermelon in half, then cut each half into wedge-shaped slices.
For rind-off cubes, slice off the green rind from each slab, then cut the red flesh into cubes.